Continue the investigations of immunologic sequelae of vasectomy previously conducted under contract N01HD22775 with the State University of New York and its subcontract with Wayne State University. The project involves collaboration between the University of Connecticut and Wayne State University; responsibility for the human studies rests with Wayne State University while responsibility for animal investigations rests with the University of Connecticut. The human and animal studies will be coordinated and findings from each aspect will be considered in ongoing work in other aspects of this joint investigation.